As an example of vehicle door lock device, a vehicle door lock device includes a latch mechanism which is mounted to a door together with a housing, as well as an open lever, an open link, and an active lever which are mounted to the housing. This type of door lock device is described in Japanese Patent Application Publication No. 2006-233507, for example. The latch mechanism is capable of holding the door in a closed state with respect to a body of the vehicle. The latch mechanism includes a latch capable of being engaged with and disengaged from a striker mounted to the body and a lift lever capable of maintaining and releasing the engaged state of the latch with respect to the striker. The open lever is actuated along with a door opening operation of a door handle provided inside or outside the door.
The open link is disposed between the open lever and the lift lever. The open link switches an operation state between an unlocked state and locked state of the vehicle door lock device. In unlocked state, an operation in a door opening direction of the open lever along with the door opening operation of the door handle is transmitted to the lift lever. In locked state, the operation in the door opening direction of the open lever is not transmitted to the lift lever. The active lever is a lock operation lever for switching the operation state of the open link to the unlocked state or the locked state. A position of the active lever is switched from an unlock position to a lock position by a locking operation of a lock/unlock operation member to bring the open link into the locked state, and is switched from the lock position to the unlock position by an unlocking operation of the lock/unlock operation member to bring the open link into the unlocked state.
According to the vehicle door lock device described in Japanese Patent Application Publication No. 2006-233507, the active lever includes a main lever rotatably mounted to the housing and associated with the lock/unlock operation member, a sub lever rotatably mounted relatively to the main lever and associated with the open link, and a spring interposed between the main lever and the sub lever and biasing the sub lever toward a predetermined position with respect to the main lever. In the door-locked state (in a state where the door is locked), when the door handle and the lock/unlock operation member are operated at a time and a panic state occurs, the spring deforms itself elastically to permit (guarantee) movement of the main lever to an unlock position and also permit return of the open link to an initial position (return position). Thus, smooth switching into the door-unlocked state (in a state where the door is locked) can be achieved.